Conventionally, fluidic devices having a flow path have been used in order to perform various operations such as separation, mixing, and an analysis of a liquid. A reagent for detecting an analyte can be placed in the flow path of the fluidic devices. Therefore, fluidic devices can be used as testing devices such as biochemical sensors for blood testing or DNA testing, and chemical sensors for quality control of foods or beverages.
In a conventional manner for placing a reagent in the flow path, a solution containing the reagent has been dropped into the flow path. For example, there is disclosed a method of dropping a solution containing a biomaterial, which is a reagent, into a spreading strip formed of nitrocellulose, which is a flow path member (see PTL 1). However, if the dropped reagent solution is spread through the spreading strip by a capillary action, a sharp signal band may not be obtained when the analyte is detected. Hence, there is disclosed that in order to control spreading of the biomaterial-containing solution, a control line is formed in the spreading strip using a casein solution or the like, and the biomaterial-containing solution is dropped in the vicinity of the control line to thereby localize the biomaterial along the control line (see PTL 1).